Diesel compression technology during deceleration - Jeep Garage - Jeep Forum

Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WK2 - > 2014+ Jeep Grand Cherokee Ecodiesel 3.0

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 03-13-2016, 10:15 PM
Member
My Jeep: 2015 3.0L WK2
 
Join Date: Oct 2015
Posts: 20
Thanks: 16
Thanked 0 Times in 0 Posts
Rep Power: 481
NorthMan is on a distinguished road
Diesel compression technology during deceleration

Does someone know if our WK2 EcoDiesel is equipped with an additional exhaust valve that will cause a backpression in the cylinder?

According to this YouTube video, there are 2 majors technologies to decelerate a diesel motor by compression:
1) Add an additional exhaust valve
2) Use Jig braking (opening cylinder's exhaust valve during compression phase to let air out)



I think our WK2 would have the first technology. I personally dislike compression performance. There is not enough to my taste.

Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 03-14-2016, 12:27 PM
Member
My Jeep: 2015 WK2
 
Join Date: Sep 2015
Location: Bay Area
Posts: 9
Thanks: 15
Thanked 1 Time in 1 Post
Rep Power: 494
chris. is on a distinguished road
Re: Diesel compression technology during deceleration

There isn't anything installed from the factory, afaik, to support engine braking. However, the GDE tune offers an engine braking option that uses the turbo vanes to monkey with the backpressure and provide some engine braking effect. Same concept as your technology number 1 above, but just using the turbo as the exhaust valve?
Reply With Quote
  #3  
Old 03-21-2016, 06:55 PM
Member
 
Join Date: Sep 2014
Posts: 123
Thanks: 5
Thanked 23 Times in 23 Posts
Rep Power: 982
hayasa is on a distinguished road
Re: Diesel compression technology during deceleration

I was under the impression that the stock set-up includes an engine braking condition using closed turbo vanes. You can feel it if you manually upshift going downhill - the rpms will jump and the car will decelerate.

I think the GDE tune eliminates it unless you opt in for their engine braking programming which takes what the factory uses and tunes it for what they consider better parameters.

Just what I heard so take with a grain of NaCl.
Reply With Quote
  #4  
Old 03-21-2016, 07:35 PM
Member
My Jeep: 2012 WK2
 
Join Date: Mar 2012
Posts: 929
Thanks: 37
Thanked 43 Times in 39 Posts
Rep Power: 1232703
2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute2012 Summit has a reputation beyond repute
Re: Diesel compression technology during deceleration

No factory engine braking that I'm aware of. Transmission braking is an option on the Ram Ecodiesel, but don't know about the JGC.
Reply With Quote
  #5  
Old 04-03-2016, 03:29 AM
ExcursionDiesel's Avatar
Premium Member
My Jeep: 2014 3.0L WK2
 
Join Date: Apr 2013
Location: W. TN.
Posts: 1,849
Thanks: 16
Thanked 284 Times in 196 Posts
Rep Power: 4074
ExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond repute
Re: Diesel compression technology during deceleration

Sure, thd CRD has natural engine braking and more if you (or the ECM) upshifts....but there is nothing mechanical other than engine friction to assist. It is much less than a gasser. On a steep hill, mine will upshift and the motor can be pushed to redline if brakes aren't used. If the VVT turbo is being used, it doesn't do much IMHO.
__________________
----------------------
The founder of JeepGarage.org, Scottina06, has a son Max who is in need of corrective surgery from an infection at birth that left one leg 4 inches short. We need to support our Jeep brothers. His family has started a fund on giveforward.com. If you have ever been helped by someone else, now is a good time to pay it forward. Here is a link to that page. God bless you! http://gfwd.at/1rz33PW
Reply With Quote
  #6  
Old 04-03-2016, 08:14 AM
Member
My Jeep: 2015 3.0L WK2
 
Join Date: Oct 2015
Posts: 20
Thanks: 16
Thanked 0 Times in 0 Posts
Rep Power: 481
NorthMan is on a distinguished road
Re: Diesel compression technology during deceleration

Compared to a gaz motor, I find wk2 ecodiesel mechanic to have mush less deceleration compression. Few months ago, I rent a Toyota 4Runner during a trip in mountain ranges. I frequently used motor compression to slow me downhill. It had a very good compression and deceleration was very effective no matter the slope steepness and vehicule speed.

Back home with my wk2, it has much less deceleration compression power than the gaz 4Runner.

I had to find a downside of my Grand Cherokee and I found it. The sole one!
Reply With Quote
  #7  
Old 04-10-2016, 01:42 AM
ExcursionDiesel's Avatar
Premium Member
My Jeep: 2014 3.0L WK2
 
Join Date: Apr 2013
Location: W. TN.
Posts: 1,849
Thanks: 16
Thanked 284 Times in 196 Posts
Rep Power: 4074
ExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond reputeExcursionDiesel has a reputation beyond repute
Re: Diesel compression technology during deceleration

Diesels have much higher compression than gas motors. What they lack is a throttle plate. Gassers have better engine braking because they can't pump more air through the motor when the throttle is closed. Engine braking is due to the vacuum created when the motor rpm increases going down a hill. Diesels pump air more freely when overdriven on a downhill grade. There are devices that block the intake or exhaust to increase engine braking but our EcoDiesels don't have anything. There is a custom ECU tune by GDE that decreases the pitch on the turbo vanes to increase resistance to exhaust flow and increase engine braking. The tune also increases performance among other things.
__________________
----------------------
The founder of JeepGarage.org, Scottina06, has a son Max who is in need of corrective surgery from an infection at birth that left one leg 4 inches short. We need to support our Jeep brothers. His family has started a fund on giveforward.com. If you have ever been helped by someone else, now is a good time to pay it forward. Here is a link to that page. God bless you! http://gfwd.at/1rz33PW
Reply With Quote
The Following User Says Thank You to ExcursionDiesel For This Useful Post:
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Whistle sound on deceleration. mattw1992 Trouble Shooting/Problems/Service 13 09-17-2014 01:10 PM
2014 SRT Whistle noise during 60-35mph deceleration 14srt Trouble Shooting/Problems/Service 60 11-06-2013 12:16 PM
Hello, WK2 suction type noise on deceleration craigb Trouble Shooting/Problems/Service 3 08-29-2013 02:27 PM
Deceleration Anyone? RAC88 Grand Cherokee SRT - WK2 6 07-28-2013 09:22 PM
Deceleration shudder on V8 mjw930 Trouble Shooting/Problems/Service 11 03-23-2011 10:11 AM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 02:39 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by FCA US LLC. Chrysler, Dodge, Jeep, Ram, Mopar and SRT are registered trademarks of FCA US LLC.